(Khizr Khan.Screenshot via MSNBC)

The father of a deceased Muslim US soldier who gave a rousing speech on the final night of the Democratic National Convention is reiterating his argument against Donald Trump's bid for the White House.

Khizr Khan called out the Republican nominee in Philadelphia on Thursday, in response to the real-estate mogul's controversial proposals to ban Muslim immigration to the US.

"That was only half of my speech," Khan said during an appearance on MSNBC Friday.

In an interview on the network, Khan appealed to top Republican leaders in Congress, asking them to reject Trump's candidacy. He specifically called on Senate Majority Leader Mitch McConnell and House Speaker Paul Ryan, describing each as a "patriot" and a "decent human being."

"Isn't it time to repudiate Trump? What he has said, what he has threatened to do. This is [a] moral imperative for both leaders to say to him, 'That's enough.'"

"You are about to sink the ship of the patriot Republicans," he added.

Khan likened the US Democratic and Republican parties as one and the same, saying, "Republicans are as patriotic as Democrats are. They are half the goodness of this beautiful country."

Appearing to fight back tears, Khan posed this question to Republicans: "If your candidate wins, and he governs the way he has campaigned, my country, this country will have [a] Constitutional crisis [like] never before."

(Khizr Khan, father of a deceased Muslim US Soldier, holds up a booklet of the US Constitution as he delivers remarks on the fourth day of the Democratic National Convention at the Wells Fargo Center in Philadelphia.Alex Wong/Getty Images)

Referring to McConnell and Ryan again, Khan added: "My conscience compels me under these very difficult circumstances ... there is so much at stake. I appeal to both of these leaders ... there comes a time in the history of a nation where an ethical, moral stand has to be taken — regardless of the political cost."

Sen. Ted Cruz of Texas carried a similar message to the Republican National Convention earlier this month. Cruz was booed off the stage during a fiery anti-Trump speech in Cleveland, Ohio, in which he chose not to endorse Trump, but to admonish voters to "stand, and speak, and vote your conscience."

Ryan suggested in June that he might sue Trump if he tried to enact a Muslim ban as president. McConnell said in May that all commanders in chief face systemic and institutional "constraints" that will prevent "big mistakes."

Watch Khizr Khan's MSNBC interview here:

Watch: #KhizrKhan asks Mitch McConnell and Paul Ryan to repudiate Trump. Tune in to @TheLastWord for the interview https://t.co/rtp6TJOySL